[php-src] Issue #10367: Using variable variables in arrow functions

Issue: https://github.com/php/php-src/issues/10367 Author: alexNecroJack ### Description The following code: ```php <?php // Variable variable. $a = 'b'; $b = 'target'; var_dump($$a == $b); // Anon function with inclusion of scope. $fn = function($c) use($b) { var_dump($$c == $b); }; $fn($a); // I can use scope within using variable variable. $fn = fn($c) => $$c == $b; var_dump($fn($a)); // I can't return it though. $fn = fn($c) => $$c; var_dump($fn($a)); ``` Resulted in this output (PHP 7.4+) : ``` bool(true) bool(true) bool(true) Warning: Undefined variable $b in /home/user/scripts/code.php on line 20 NULL ``` But I expected this output instead: ``` bool(true) bool(true) bool(true) string('target') ``` Credits and all to: @kschatzle I'm only sharing this (found on google, github issues search returned nothing, documentation states nothing...) [ArrowFunctionScoping](https://gist.github.com/kschatzle/ce7f49df41f26093079dcc1b45fbefe7) ### PHP Version PHP 8.1.12, PHP 8.0.25 ### Operating System https://onlinephp.io/